Summary:

The Mowing Experiment Biophysical Measurements data set was collected to quantify the effects of grazing and nitrogen fertilization on primary productivity and plant chemistry. The data in this data set quantified the effects of foliage removal on plant net primary productivity (NPP), plant nutrient content and the effects of grazing pressure as simulated by mowing.

Mean values and their variances are reported. Standing crop values reflect treatment effects of removing biomass periodically, but the productivity levels show the inverse effects, suggesting plant compensatory growth mechanisms. Grazing intensity was defined as the amount of leaf area remaining following defoliation. The latter was manipulated experimentally by mowing at several heights. Grazing frequency was defined as the number of times foliage removal occurred in each year and included grazing and mowing history as well as current mowing frequency.

1. Data Set Overview:

Data Set Identification:

Data Set Introduction:

The data in this data set quantified the effects of foliage removal on plant net primary productivity (NPP), plant nutrient content and the effects of grazing pressure as simulated by mowing. Mean values and their variances are reported.

Objective/Purpose:

These data were collected to quantify the effects of grazing and nitrogen fertilization on primary productivity and plant chemistry.

Requested Form of Acknowledgment.

3. Theory of Measurements:

To evaluate the effects of frequency and intensity of defoliation on plant responses of native tallgrass prairie, grazing intensity was defined as the amount of leaf area remaining following defoliation. The latter was manipulated experimentally by mowing at several heights. Grazing frequency was defined as the number of times foliage removal occurred in each year and included grazing and mowing history as well as current mowing frequency.

Principles of Operation:

Sensor/Instrument Measurement Geometry:

Manufacturer of Sensor/Instrument:

Not applicable.

Calibration:

Specifications:

Not applicable.

Tolerance:

Not applicable.

Frequency of Calibration:

Not applicable.

Other Calibration Information:

Not applicable.

5. Data Acquisition Methods:

The intensity and frequency experiments were done at one area close to but not on FIFE sites 6, 31, and 29 (SITEGRID 2123-MOW, 2139-MOW, and 0847-MOW). Both of these experiments were done in native tallgrass prairie. Both the frequency and intensity measurements were made within 10 meters of each other.

A detailed description of the plots, the quadrats and the sampling techniques used in these experiments is given in Turner et al. (1993).

Intensity experiment:

In 1987, a mowing intensity experiment was superimposed on 24, 10 x 5 m plots established in early 1985. Prior to the experimental treatments initiated in 1985, the site had not been grazed for 10 years. The site had been frequently burned in spring during this interval. The objective of these experiments was to estimate standing crop and the amount of foliage removal by mowing the plots. In 1987, these plots were used to create six replicates of the following mowing treatments: (1) unmowed (control), (2) mowed to 5 cm above ground level, (3) mowed to 10 cm, and (4) mowed to 20 cm. Mowing of the whole plots was conducted as needed to maintain vegetation at treatment heights, and all plots were mowed on each sampling date. Samples were obtained by hand clipping all vegetation within 0.1 square meter quadrats to ground level (for standing crop estimate) or above specified treatment heights (for use in production estimate), oven-drying to constant weight, and weighing. Samples were sorted into grass and non-grass components prior to drying.

A similar experiment was conducted in a planted brome field near site 2 (SITEGRID 1916-MOW, BROME). The experimental design was similar to the intensity experiment. Plots were mowed to the same heights as in the intensity experiments. Fertilizer was added to half of the plots. There were 3 replicates for the unfertilized plots at each of the 4 mowing heights (i.e., 5, 10, 20 cm and no mowing), and 3 replicates for the fertilized plots at each of the 4 moving heights. Each plot was treated with ammonium nitrate fertilizer at a rate of 10 [g N][m^2].

Frequency experiment:

In a separate mowing frequency experiment, also conducted in 1987, plots that had not been mowed or grazed for ten years were used. These plots were located adjacent to mowing intensity experiment plots and were burned on the same schedule as intensity experiment plots. The mowing frequency experiment consisted of 12, 10 x 5 m plots and 8, 10 x 10 m plots randomly assigned to create 5 replicates of the following mowing treatments: (1) unmowed (control), (2) mowed 1 time, (3) mowed 3 times, and (4) mowed 6 times during the growing season. All plots were mowed as close to the soil surface (approx. 2 cm) as possible. Above-ground standing crop was sampled by clipping at ground level in one 0.1 square m quadrat per plot just prior to mowing.

The procedure used to quantify the nitrogen and phosphorous content of plant samples is detailed in Turner et al. (1993).

6. Observations:

Data Notes:

Not available.

Field Notes:

None.

7. Data Description:

Spatial Characteristics:

The FIFE study area, with areal extent of 15 km by 15 km, is located south of the Tuttle Reservoir and Kansas River, and about 10 km from Manhattan, Kansas, USA. The northwest corner of the area has UTM coordinates of 4,334,000 Northing and 705,000 Easting in UTM Zone 14.

Temporal Coverage Map:

Temporal Resolution:

Data Characteristics:

The SQL definition for this table is found in the MOW_BIOP.TDF file located on FIFE CD-ROM Volume 1.

Parameter/Variable Name Parameter/Variable Description Range Units Source
SITEGRID_ID
This is a FIS grid location code. FIS
Site grid codes (SSEE-III) give
the south (SS) and east (EE) cell
number in a 100 x 100 array of 200
meter square cells. The last 3
characters (III) are an instrument
identifier.
STATION_ID
The station ID designating the 150, FIS
location of the observations. 151,
152
OBS_DATE
The date of the observations. min = 07-MAY-87, KSU
max = 28-OCT-87
MOW_HEIGHT *
If this record is from the mowing min = 0, TAPE
height experiment, this column max = 20 MEASURE
contains the mowed height of the
vegetation in cm, otherwise this
column is null.
MOW_FREQ **
If this record is from the mowing min = 0, KSU
frequency experiment, the value is max = 6
for the number of times the site
was mowed during the growing
season, otherwise this column is
null.
FERTILIZER
If this column is from the brome F, KSU
sites of the mowing height N
experiment this column tells if
the site was fertilized, F for
fertilized, N for no fertilizer,
otherwise this column is null.
NUM_OBS
The number of experimental plots min = 3, KSU
in sample. max = 6
MEAN_GRASS_BIOMASS
The mean above ground grass min = 40.5, KSU
biomass on the day of observation max = 570.8
in g/m2.
STD_ERR_GRASS_BIOMASS
The standard error of the mean min = 4.11, KSU
grass biomass on the day of max = 84.35
observation.
MEAN_FORB_BIOMASS
The mean forb (non-grass, min = 0, KSU
non-woody vegetation) above- max = 77.8
ground biomass on the day of
observation in g/m2.
STD_ERR_FORB_BIOMASS
The standard error of the mean min = 0, KSU
forb biomass on the day of max = 26.23
observation.
MEAN_TOT_BIOMASS
The mean total (grass + forb) min = 87.1, KSU
above ground biomass on the max = 595.7
day of observation in g/m2.
STD_ERR_MEAN_TOT_BIOMASS
The standard error of the mean min = 6.13, KSU
total biomass on the day of max = 102.71
observation.
MEAN_GRASS_PROD
The mean grass biomass produced min = 237.5, KSU
since beginning of growing season max = 919
(standing crop + cumulative
harvest) in g/m2.
STD_ERR_GRASS_PROD
The standard error of the mean min = 5.45, KSU
grass biomass produced since max = 84.35
beginning of growing season.
MEAN_FORB_PROD
The mean forb (non-grass, min = 0, KSU
non-woody vegetation) biomass max = 77.8
produced since beginning of
growing season (standing crop
+ cumulative harvest) in g/m2.
STD_ERR_FORB_PROD
The standard error of the mean min = 0, KSU
forb (non-grass, non-woody max = 45.65
vegetation) biomass produced since
beginning of growing season.
MEAN_TOT_PROD
The mean total (grass + forb) min = 254.1, KSU
biomass produced since beginning max = 962.6
of growing season (standing crop
+ cumulative harvest) in g/m2.
STD_ERR_MEAN_TOT_PROD
The standard error of the mean min = 1.44, KSU
total (grass + forb) biomass max = 102.71
produced since beginning of the
growing season.
GRASS_N2_CONC
The nitrogen concentration in min = 0.532, NITROGEN
grasses as percent dry weight. max = 2.372 ANALYZER
STD_ERR_GRASS_N2_CONC
The standard error of nitrogen min = 0.0277, KSU
concentration in grasses. max = 0.1919
GRASS_PHOS_CONC
The phosphorus concentration in min = 0.056, KSU
grasses as percent dry weight. max = 0.271
STD_ERR_GRASS_PHOS_CONC
The standard error of the min = 0.0084, KSU
phosphorus concentration in max = 0.0405
grasses.
FIFE_DATA_CRTFCN_CODE ***
The FIFE certification level of CPI=Checked FIS
the data. by Principal
Investigator
LAST_REVISION_DATE
The date the data was last min = 12-JUL-90, FIS
revised. max = 13-JUL-90

Footnotes:

* Mowing height treatment:

0 = unmowed control

5 = mowed to 5 cm above ground

10 = mowed to 10 cm above ground

20 = mowed to 20 cm above ground

** Mowing frequency treatment:

0 = unmowed control

1 = mowed one time during growing season

3 = mowed three times during growing season

6 = mowed six times during growing season

*** Decode the FIFE_DATA_CRTFCN_CODE field as follows:

The primary certification codes are: EXM Example or Test data (not for release) PRE Preliminary (unchecked, use at your own risk) CPI Checked by Principal Investigator (reviewed for quality) CGR Checked by a group and reconciled (data comparisons and cross checks)

The certification code modifiers are: PRE-NFP Preliminary - Not for publication, at the request of investigator. CPI-MRG PAMS data which is "merged" from two separate receiving stations to eliminate transmission errors. CPI-??? Investigator thinks data item may be questionable.

8. Data Organization:

Data Granularity:

The overall time period of data acquisition was from May 7, 1987 through October 28, 1987 during the IFCs. Data were collected within 0.1 square meter quadrats to ground level. Samples were obtained by hand clipping all vegetation within 0.1 square meter quadrats to ground level (for standing crop estimate) or above specified treatment heights (for use in production estimate), oven-drying to constant weight, and weighing.

A general description of data granularity as it applies to the IMS appears in the EOSDIS Glossary.

Data Format:

The CD-ROM file format consists of numerical and character fields of varying length separated by commas. The character fields are enclosed with a single apostrophe. There are no spaces between the fields. Each file begins with five header records. Header records contain the following information: Record 1 Name of this file, its table name, number of records in this file, path and name of the document that describes the data in this file, and name of principal investigator for these data. Record 2 Path and filename of the previous data set, and path and filename of the next data set. (Path and filenames for files that contain another set of data taken at the same site on the same day.) Record 3 Path and filename of the previous site, and path and filename of the next site. (Path and filenames for files of the same data set taken on the same day for the previous and next sites (sequentially numbered by SITEGRID_ID)). Record 4 Path and filename of the previous date, and path and filename of the next date. (Path and filenames for files of the same data set taken at the same site for the previous and next date.) Record 5 Column names for the data within the file, delimited by commas. Record 6 Data records begin.

Each field represents one of the attributes listed in the chart in the Data Characteristics Section and described in detail in the TDF file. These fields are in the same order as in the chart.

9. Data Manipulations:

Formulae:

Derivation Techniques and Algorithms:

Total weight is the sum of grass and non-grass dry weight for a date and site. Cumulative above-ground biomass production was calculated for each plot by summing the estimates of biomass removed by previous mowing and the current standing crop at each date.

Mass of nitrogen (N) and phosphorus (P) incorporated into above-ground tissues was estimated by multiplying percent concentration and biomass.

Data Processing Sequence:

Processing Steps:

Not available at this revision.

Processing Changes:

None.

Calculations:

Special Corrections/Adjustments:

None.

Calculated Variables:

Mass of nitrogen.

Mass of phosphorous.

Cumulative above-ground biomass production.

Graphs and Plots:

None.

10. Errors:

Sources of Error:

Not available at this revision.

Quality Assessment:

Data Validation by Source:

Not available at this revision.

Confidence Level/Accuracy Judgment:

The investigator places a high degree of confidence in the accuracy of these data.

Measurement Error for Parameters:

Additional Quality Assessments:

FIS staff applied a general Quality Assessment (QA) procedure to the data to identify inconsistencies and problems for potential users. As a general procedure, the FIS QA consisted of examining the maximum, minimum, average, and standard deviation for each numerical field in the data table. An attempt was made to find an explanation for unexpected high or low values, values outside of the normal physical range for a variable, or standard deviations that appeared inconsistent with the mean. In some cases, histograms were examined to determine whether outliers were consistent with the shape of the data distribution.

Data Verification by Data Center:

The data verification performed by the ORNL DAAC deals with the quality of the data format, media, and readability. The ORNL DAAC does not make an assessment of the quality of the data itself except during the course of performing other QA procedures as described below.

The FIFE data were transferred to the ORNL DAAC via CD-ROM. These CD-ROMs are distributed by the ORNL DAAC unmodified as a set or in individual volumes, as requested. In addition, the DAAC has incorporated each of the 98 FIFE tabular datasets from the CD-ROMs into its online data holdings. Incorporation of these data involved the following steps:

copying the entire FIFE Volume 1, maintaining the directory
structure on the CD-ROM.

using data files, documentation, and SQL code provided on
the CD-ROM to create a database in Statistical Analysis System
(SAS).

Each distinct type of data (i.e. "data set" on the CD-ROM), is accompanied by a documentation file (i.e., .doc file) and a data format/structure definition file (i.e., .tdf file). The data format files on the CD-ROM are Oracle SQL commands (e.g., "create table") that can be used to set up a relational database table structure. This file provides column/variable names, character/numeric type, length, and format, and labels/comments. These SQL commands were converted to SAS code and were used to create SAS data sets and subsequently to input data files directly from the CD-ROM into a SAS dataset. During this process, file names and directory paths were captured and metadata was extracted to the extent possible electronically. No files were found to be corrupted or unreadable during the conversion process.

Additional Quality Assurance procedures were performed as follows:

Statistical operations were performed to calculate minimum
and maximum values for all numeric fields and to create a listing
of all values of the character fields. During this process, it
was determined that various conventions were used to represent
missing values. (Note: no modifications were made to any data
by the DAAC). In most cases, missing value identification conventions
were discussed in the accompanying .doc file. Based on a visual
check of the minimum and maximum values, no glaring errors or
holes were identified that might indicate errors introduced during
CD-ROM mastering by the FIFE project or data ingest by the DAAC.

Some minor inconsistencies and typographical errors were identified
in some of the character fields and column labels, however, no
modifications were made to the data by the DAAC.

Some conversions of ASCII data were necessary to move the
data from a DOS platform to a UNIX platform. Standard operating
system conversion utilities were used (e.g., dos2unix).

Much of the metadata required for archival is imbedded in
the narrative documentation accompanying the data sets and extracted
manually by DAAC staff who have read the .doc files provided on
the CD-ROM and have hand entered this information into the metadata
database maintained by the DAAC. QA procedures have been performed
on these metadata to identify and eliminate typographical errors
and inconsistencies in naming conventions, to ensure that all
required metadata is present, and to ensure the accuracy of file
names and paths for retrieval.

Data requested for distribution to users are checked to verify
that files copied from disk to other media remain uncorrupted.

As errors are discovered in the online tabular data by investigators, users, or DAAC staff, corrections are made in cooperation with the principal investigators. These corrections are then distributed to users. CD-ROM data are corrected when re-mastering occurs for replenishment of CD-ROM stock.

11. Notes:

Limitations of the Data:

Not available.

Known Problems with the Data:

None known at this revision.

Usage Guidance:

Not available at this revision.

Any Other Relevant Information about the Study:

The Exotech Surface Reflectances for the Mowing Experiment data (on FIFE CD-ROM Volume 1) were collected as a companion data set to the data described here. The sampling interval for these exotech data was more frequent than the mowing data. On some occasions the exotech was run the day before, the day of, and the day after the mowing of the plots. The Root Biomass data were also collected as a companion data set.

12. Application of the Data Set:

The data in this data set can be used to quantify the effects of foliage removal on plant net primary productivity (NPP), plant nutrient content and the effects of grazing pressure.

13. Future Modifications and Plans:

The FIFE field campaigns were held in 1987 and 1989 and there are no plans for new data collection. Field work continues near the FIFE site at the Long-Term Ecological Research (LTER) Network Konza research site (i.e., LTER continues to monitor the site). The FIFE investigators are continuing to analyze and model the FIFE data from the field campaigns to produce new data products.

14. Software:

Software to access the data set is available on the all volumes of the FIFE CD-ROM set. For a detailed description of the available software see the Software Description Document.

The format used for the filenames is: 1987grid.sfx, where grid is the four number code for the location within the FIFE site grid. The filename extension (.sfx), identifies the data set content for the file (see the Data Characteristics Section) and is equal to .MBP for this data set.

17. References:

Satellite/Instrument/Data Processing Documentation.

Nelson, D.W., and L.E. Sommers. 1980. Total nitrogen analysis of soil and plant tissues. J. of the Assoc. of Official Analytical Chemists. 63:770-778.

Archive/DBMS Usage Documentation.

Contact the EOS Distributed Active Archive Center (DAAC) at Oak Ridge National Laboratory (ORNL), Oak Ridge, Tennessee (see the Data Center Identification Section). Documentation about using the archive and/or online access to the data at the ORNL DAAC is not available at this revision.

20. Document Information:

May 6, 1994 (citation revised on October 14, 2002).

Warning: This document has not been checked for technical or editorial accuracy by the FIFE Information Scientist. There may be inconsistencies with other documents, technical or editorial errors that were inadvertently introduced when the document was compiled or references to preliminary data that were not included on the final CD-ROM.

Previous versions of this document have been reviewed by the Principal Investigator, the person who transmitted the data to FIS, a FIS staff member, or a FIFE scientist generally familiar with the data.